[Comparative study of Vitek-2™ AIX versus Vitek-2™ PC: phenotypic resistance of enterobacteriaceae to ß-lactams]. / Comparaison du Vitek-2™ AIX versus Vitek-2™ PC par l'étude des phénotypes de résistance des entérobactéries aux ß-lactamines.

AIM OF THE STUDY: Vitek-2™ AIX versus Vitek-2™ PC have different rules for phenotypic interpretation. The aim of this study is to ensure that the raw results determined by these two versions of Vitek-2™ allow biologists to conclude to the same resistance phenotype, but also to evaluate their own phenotypic interpretation system (advanced expert system). MATERIAL AND METHODS: A total of 251 strains of Enterobacteriaceae of different groups and phenotypes was tested. Each strain was studied simultaneously on both types of Vitek-2™ from the same calibrated inoculum. We then compared their resistance phenotype to beta-lactams. RESULTS: For strains not producing ESBL or CHN, the biologist concluded in 99.3% of cases to the same resistance phenotype by interpreting the raw results of Vitek-2™ AIX versus PC. The phenotypic interpretation of biologist is different from the Vitek-2™ in respectively 40% versus 43% of cases for AIX and PC versions. For multi-resistant strains, the biologist concluded in 100% of cases to the same resistance phenotype by interpreting the raw results of Vitek-2™ AIX versus PC. In 51.5% of cases the biologist use the disk diffusion method (DD). The results of this technique put forward 29% discrepancy with the two types of Vitek-2™. Finally, when Vitek-2™ claims the presence of an ESBL alone, this result is routinely confirmed by DD. CONCLUSION: The switch from Vitek-2™ AIX to Vitek-2™ PC does not alter the results of the phenotypic interpretation of biologist.

Virulence factors produced by strains of Staphylococcus aureus isolated from urinary tract infections.

Staphylococcus aureus infections are widely prevalent in West Africa and are often associated with urinary tract infections (UTIs). Virulence factors from S. aureus have rarely been described for such infections. The purpose of the current study was to determine the prevalence of toxins and adhesion factors obtained from S. aureus isolated from presumed primary UTIs at the Cotonou University Hospital (CUH) in Benin as compared with the Strasbourg University Hospital (SUH) in France. Both ambulatory and hospitalised patients were included in the study. Sixty-five independent strains of S. aureus from CUH and 35 strains from SUH were obtained over a four-month period. Virulence factors were characterised by immunodetection or multiplex polymerase chain reaction, and meticillin susceptibility was recorded. Approximately 50% of all isolates produced at least one enterotoxin. No isolate from SUH produced Panton-Valentine leucocidin (PVL), whereas 21.5% of the S. aureus isolates from CUH produced PVL (P<0.01). Six of 14 (43%) PVL-positive isolates were meticillin-resistant. At SUH, the incidence of MRSA (57%) was significantly higher (P<0.01) than at CUH (14%). Genes encoding clumping factor B, and elastin and laminin binding proteins were detected in almost all isolates (80%), irrespective of the geographical origin. The results for elastin binding protein differed significantly from published data regarding isolates from other clinical origins. Staphylococcal toxins and adhesion factors may be important in the physiopathology of UTI.

[Invasive Streptococcus agalactiae infections in non-pregnant adults]. / Les infections invasives à Streptococcus agalactiae chez l'adulte (femme enceinte exclue).

OBJECTIVES: Streptococcus agalactiae (Group B streptococcus) is a major cause of invasive diseases in non-pregnant adults, particularly in the elderly and those with underlying conditions. We describe these conditions and clinical characteristics of patients followed in our teaching hospital. METHODS: We retrospectively reviewed clinical records of 64 patients with S. agalactiae-related invasive infection, hospitalized between January 1997 and January 2006. RESULTS: The mean age of patients was 59 (+/-17 years). The H:F sex ratio was 1.06. At least one underlying condition was found in 90.6%. Diabetes mellitus (43.7%), peripheral vascular disease (34.4%), myocardial ischemia (20.3%) and malignant neoplasms (20.3%) were among the most frequent conditions. The mean index of comorbidity (Charlson) was 2.5 (+/-2). Common clinical manifestations included infection of the urinary tract (32.8%), skin and soft-tissue (25%), and osteoarthritis (21.9%). Bacteremia occurred in 31.2% with no identified source in 2 patients. During the first month, 2 cases of endocarditis, 1 case of meningitis, and 4 deaths occurred. CONCLUSION: We confirm the importance of underlying diseases in the emergence of S. agalactiae infections.

VISLISI trial, a prospective clinical study allowing identification of a new metalloprotease and putative virulence factor from Staphylococcus lugdunensis.

OBJECTIVE: Staphylococcus lugdunensis is a coagulase-negative staphylococcus that displays an unusually high virulence rate close to that of Staphylococcus aureus. It also shares phenotypic properties with S. aureus and several studies found putative virulence factors. The objective of the study was to describe the clinical manifestations of S. lugdunensis infections and investigate putative virulence factors. METHOD: We conducted a prospective study from November 2013 to March 2016 at the University Hospital of Strasbourg. Putative virulence factors were investigated by clumping factor detection, screening for proteolytic activity, and sequence analysis using tandem nano-liquid chromatography-mass spectrometry. RESULTS: In total, 347 positive samples for S. lugdunensis were collected, of which 129 (37.2%) were from confirmed cases of S. lugdunensis infection. Eighty-one of these 129 patients were included in the study. Bone and prosthetic joints (PJI) were the most frequent sites of infection (n=28; 34.6%) followed by skin and soft tissues (n=23; 28.4%). We identified and purified a novel protease secreted by 50 samples (61.7%), most frequently associated with samples from deep infections and PJI (pr 0.97 and pr 0.91, respectively). Protease peptide sequencing by nano-liquid chromatography-mass spectrometry revealed a novel protease bearing 62.42% identity with ShpI, a metalloprotease secreted by Staphylococcus hyicus. CONCLUSION: This study confirms the pathogenicity of S. lugdunensis, particularly in bone and PJI. We also identified a novel metalloprotease called lugdulysin that may contribute to virulence.

[A young woman with granulomatous mastitis: a corynebacteria may be involved in the pathogenesis of these disease]. / Mastite granulomateuse récidivante chez une jeune femme: rôle potentiel de "corynebacterium kroppenstedtii".

INTRODUCTION: The granulomatous mastitis is an inflammatory pseudotumor of the breast of which evolution benign but likely to generate important morphological after-effects among young women. This anatomoclinic entity of dubious etiology until these last years poses a problem of differential diagnosis with other etiologies of granulomatosis and especially with inflammatory carcinoma of the breast. The infectious theory is actually based on solid arguments and mainly explains the physiopathology of this affection. INTERPRETATION: A 26 years old young woman developed an inflammatory tumor of the left breast of which the catch of load by surgery and an antibiotherapy had shown trailing local continuations and of the esthetic after-effects. One year later, a very inflammatory repetition on the level of the right breast was dealt with in a different way: by steroids and immunomodulating drugs associated with iterative punctures with the purulent collections, the objective being to be less dilapidating that left side. The initial answer was rather favorable and encouraging but the purulent reappearance bulky granulomas with sinus way made reconsider the therapeutic attitude and antibiotics were undertaken after description of a lipophilic corynebactery in the material of puncture (Corynebacteria kroppenstedtii). The effectiveness of the amoxicilline introduced on the data of the antibiogram was undeniable. CONCLUSION: This observation illustrates the therapeutic and diagnostic difficulties of an exceptional affection. Potentially accessible to antibiotics it generally requires a joint surgical assumption of responsibility, at the same time to ensure the histological diagnosis but also with a therapeutic aim. The interest of steroids and the immunomodulation by methotrexate is debatable, these treatments cannot however be conceived without antibiotherapy and sometimes surgery.

[Actinomycosis of the buttock]. / Actinomycose fessière.

INTRODUCTION: Cutaneous actinomycosis of the buttocks is a rare granulomatous bacterial infection that usually starts in the perianal area. We present an exceptional case in the form of a pseudo-tumor. CASE REPORT: A 69 year-old woman, in general good health, developed an indurate mass on the supra-external quadrant of the right buttock. The tumor was centered by an ulcerated nodule with a diameter of around 10 centimeters. Imaging showed invasion of the soft tissue of the skin in the internal psoas muscle, the adipose tonality of which was compatible with a liposarcoma. The skin biopsy revealed characteristic bacterial grain in the center of a cholesterol granuloma. Subsequent culture in aerobic milieu identified Actinomyces gerencseriae. Cure was obtained following complete exeresis of the fibrous tissue and 8 months of antibiotic amoxicillin-clavulanic acid therapy. DISCUSSION: Other than the most unusual clinical aspect, the originality of this case of actinomycosis of the buttocks is based on its potential appendix origin, 4 years after acute appendicitis, with slow posterior fistulation. Other cases of actinomycosis of appendix origin have been reported and its delayed onset following the intervention has been documented. The pseudo-sarcomatous aspect was responsible for diagnostic wandering. The histological image and, subsequently, the results of the bacteriological culture confirmed the diagnosis.

Contribution of high-performance liquid chromatography to the identification of some Corynebacterium species by comparison of their corynomycolic acid patterns.

Reverse-phase high-performance liquid chromatography of corynomycolic acids provided a specific pattern for each Corynebacterium species studied. These data suggest that a fast and reproducible procedure is now available for bacteriological identification at the genus and at the species level of corynomycolic-acid-containing bacteria. Mass spectrometry analysis of post-column collected fractions provided the order of elution of some corynomycolic acids and isomers and showed the high specificity of the chromatographic assay which could be used for the routine bacteriological identification of some species belonging to the genus Corynebacterium.

Evaluation of the applicability of amplified rDNA-restriction analysis (ARDRA) to identification of species of the genus Corynebacterium.

The 16S rRNA genes (rDNA) of 50 strains belonging to 26 different coryneform bacterial species and genomospecies and of the type strain of Rhodococcus equi were enzymatically amplified. Amplified rDNA restriction analysis (ARDRA) with the enzymes AluI, CfoI and RsaI was carried out. The combination of the ARDRA patterns obtained after restriction with these three different enzymes enabled the differentiation between the following species: Corynebacterium accolens (number of strains = 2), C. afermentans subsp. afermentans (2), C. afermentans subsp. lipophilum (2), C. amycolatum (3), CDC coryneform group ANF-1-like (1), CDC coryneform group ANF-3-like (1), C. cystitidis (1), C. diphtheriae (4), C. jeikeium (3), C. macginleyi (2), C. minutissimum (1), C. pilosum (1), C. pseudotuberculosis (2), C. renale (2), C. striatum (2), C. urealyticum (3), C. xerosis (1), CDC coryneform groups B-1 (2), B-3 (2), F-1, genomospecies 1 and 2 (6), G, genomospecies 1 (1) and G, genomospecies 2 (2). The following strains or species could not be differentiated from each other: C. pseudodiphtheriticum (2) from C. propinquum (former CDC coryneform group ANF-3) (2), CDC coryneform group F-1, genomospecies 1 (4) from genomospecies 2 (2) and C. jeikeium genomospecies A (1) from genomospecies C (2). ARDRA may represent a possible alternative for identification of coryneforms, since this technique enabled the identification of most coryneforms tested and since DNA extraction (i.e. cell lysis by boiling), amplification, restriction and electrophoresis can be carried out within 8 hours. This might allow quick identification of C. diphtheriae and other possible pathogens of the genus Corynebacterium.

Corynebacterium group D2 ("Corynebacterium urealyticum") constitutes a new genomic species.

Twenty-one Corynebacterium group D2 ("C. urealyticum") strains were found to constitute a tight DNA hybridization group distinct from named Corynebacterium species. The strains of Corynebacterium group D2 had cell wall component type IV, short chain mycolic acids and G+C content of DNA of 65-66 mol %. Corynebacterium group D2 constitutes a genomic species which can be identified by phenotypic tests.

Taxonomy of Corynebacterium diphtheriae and related taxa, with recognition of Corynebacterium ulcerans sp. nov. nom. rev.

Levels of genomic DNA relatedness were determined using a S1 nuclease procedure for reference bacteria identified as biotypes of Corynebacterium diphtheriae, biovars of Corynebacterium pseudotuberculosis, and 'Corynebacterium ulcerans'. These results showed that the three species are separate taxa at the genomospecies level whereas biotypes and biovars are closely related genomically within each species. Phylogenetic analyses of small-subunit rDNA sequences revealed that 'Corynebacterium ulcerans' forms a tight cluster with Corynebacterium pseudotuberculosis within the robust branch that groups all Corynebacterium sequenced to date. Therefore, we propose that the species incertae sedis 'C. ulcerans' should be conclusively recognized as a distinct species within the genus Corynebacterium with strain CCUG 2708 = NCTC 7910 as type strain. This species is characterized by urease production and fermentation of glycogen.

[Bacteriological and clinical aspects of corynebacterium]. / Les corynébactéries, aspects bactériologiques et cliniques.

The microbiologists use the term corynebacteria to describe aerobically growing, asporogenous, irregularly sharped gram-positive rods. They comprise strictly aerobic bacteria isolated from environment as well as preferentially anaerobic bacteria found in clinical specimens. A large part of these bacteria is considered as commensal of skin and mucous membranes. This group of organisms has recently been subjected to considerable taxonomic revisions, which have resulted in the proposal of several new species, many of them representing previous Centers for Diseases Control coryneform groups. Moreover, recent investigations demonstrated the existence of a pathogenic role for some of them. These bacteria comprise well-known pathogens such as C. diphtheriae responsible for diphtheria, Actinomyces spp. responsible for actinomycosis and Arcanobacterium haemolyticum recovered from pharyngitis, but other corynebacteria were related to particular infections. For example, the lipophilic and antibiotics multiresistant species Corynebacterium urealyticum and C. jeikeium were found to be responsible for urinary tract infections and septicemias, respectively. The recently described species Turicella otitidis was found to be implicated in otitis media and C. seminale were recovered from genital specimens of male patients. Implantation of material devices, use of broad-spectrum antibiotics led to an increase of sepsis due to the species C. jeikeium and C. amycolatum. Many of the new Actinomyces species grow well under aerobic conditions and are often implicated in various abscesses. Moreover an increase of immunocompromised patients led to the development of infections due to the aerobic actinomycete Rhodococcus equi. The association of some corynebacteria with particular diseases should prompt the microbiologist to identify these bacteria when they are encountered in a pathogenic situation. Identification of the major part of corynebacteria isolated from clinical specimens can now be achieved by using recent schemes.

[Interest of typing methods to study Corynebacterium diphtheriae strains.]. / Apport des méthodes de typage dans l'étude des souches de Corynebacterium diphtheriae.

Corynebacterium diphtheriae is the causative agent of Diphtheria. This bacteria circulates throughout the world. Recently, two outbreaks occurred in New independent states (Russia, Ukraine...) and Algeria. Routine technics permit to study the strains of Corynebacterium diphtheriae : biotype, antibiotype, toxin gene detection. However, molecular biological tests (ribotyping, and pulsed field gel electrophoresis) are necessary to characterize these strains in the space and the time. The studies with international laboratories exchanges are recents and have permitted first results concerning the molecular epidemiology of C. diphtheriae strains.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry identifies 90% of bacteria directly from blood culture vials.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is now widely used for marker/multi-biomarker detection in medical diagnosis. We tested a new protocol for bacterial identification from blood culture broths in hospital routine by using collection tubes with separator gels on 503 included samples examined over 3 months, where 1.5 mL was injected by a syringe into BD Vacutainer tubes from BACTEC-positive bottles, before processing for bacterial protein extraction. Samples were loaded in duplicate onto the MALDI MS target, allowing a series of 12 samples to be processed in duplicate within 80 min by using Biflex III and BioTyper 2.0 software (Bruker). Including polymicrobial samples, 193 of 213 of Gram-negative bacteria (91.08%) and 284 of 319 of Gram-positive bacteria (89.02%) were correctly identified at the species level. Enterobacteriaceae constituted 35.15% of all species found, Staphylococaceae 37.96%, Streptococaceae and Enterococaceae 20.85%, Pseudomonadaceae 1.69%, and anaerobes 2.44%. In most of the polymicrobial samples, one of the species present was identified (80.9%). Seven isolates remained misidentified as Streptococcus pneumoniae, all belonging to Streptococcus mitis. Staphylococcus aureus was identified better when grown on anaero-aerobic medium, and MALDI BioTyper identification scores as low as 1.4 were pertinent, provided that four successive proposals of the same species were given. This new protocol correlates with conventional microbiology procedures by up to 90%, and by >95% for only monomicrobial samples, and provides a decreased turn-around time for identification of bacteria isolated from blood cultures, making this technology suitable also for blood cultures, with less delay and cost decreases in bacterial diagnostics, and favouring better care of patients.

Catalase-negative Actinomyces neuii subsp. neuii isolated from an infected mammary prosthesis.

In this case report a catalase-negative strain of Actinomyces neuii subsp. neuii is described as the possible causative agent of an infected mammary prosthesis. DNA hybridization studies and 16S rRNA analysis confirmed that the strain belongs to the species Actinomyces neuii subsp. neuii. Since this strain is the first A. neuii subsp. neuii strain reported to be catalase negative, the catalase reaction should no longer be considered a key reaction for the diagnosis of this species but must be interpreted in conjunction with other characteristics.

Species identities and antimicrobial susceptibilities of corynebacteria isolated from various clinical sources.

Over a 14-month period, 415 clinical isolates of coryneform gram-positive rods were recovered from various sources and identified to the species level according to recent identification schemes. Corynebacterium urealyticum, Corynebacterium striatum, Corynebacterium amycolatum, and Corynebacterium jeikeium predominated, accounting for 63% of all isolates. Corynebacterium accolens, Corynebacterium striatum, Corynebacterium argentoratense, Corynebacterium propinquum and Corynebacterium pseudodiphtheriticum were mostly recovered from the respiratory tract, whereas Corynebacterium afermentans, CDC group G, and Corynebacterium jeikeium were mainly isolated from blood. None of the isolates was identified as Corynebacterium diphtheriae or Corynebacterium xerosis. Ampicillin resistance was detected in Corynebacterium jeikeium (96%) and Corynebacterium urealyticum (99%) and varied among Corynebacterium amycolatum (56%) and CDC group G (26%). These data emphasize the need for an accurate identification of coryneform organisms at the species level and for antimicrobial susceptibility testing of these organisms.

Multicenter evaluation of the updated and extended API (RAPID) Coryne database 2.0.

In a multicenter study, 407 strains of coryneform bacteria were tested with the updated and extended API (RAPID) Coryne system with database 2.0 (bioMérieux, La-Balme-les-Grottes, France) in order to evaluate the system's capability of identifying these bacteria. The design of the system was exactly the same as for the previous API (RAPID) Coryne strip with database 1.0, i.e., the 20 biochemical reactions covered were identical, but database 2.0 included both more taxa and additional differential tests. Three hundred ninety strains tested belonged to the 49 taxa covered by database 2.0, and 17 strains belonged to taxa not covered. Overall, the system correctly identified 90.5% of the strains belonging to taxa included, with additional tests needed for correct identification for 55.1% of all strains tested. Only 5.6% of all strains were not identified, and 3.8% were misidentified. Identification problems were observed in particular for Corynebacterium coyleae, Propionibacterium acnes, and Aureobacterium spp. The numerical profiles and corresponding identification results for the taxa not covered by the new database 2.0 were also given. In comparison to the results from published previous evaluations of the API (RAPID) Coryne database 1.0, more additional tests had to be performed with version 2.0 in order to completely identify the strains. This was the result of current changes in taxonomy and to provide for organisms described since the appearance of version 1.0. We conclude that the new API (RAPID) Coryne system 2.0 is a useful tool for identifying the diverse group of coryneform bacteria encountered in the routine clinical laboratory.

Identification of Corynebacterium glucuronolyticum strains from the urogenital tract of humans and pigs.

Bacterial strains isolated from the genital tracts of humans (predominantly males), semen of boars, and uterine and vaginal secretions of sows were identified as Corynebacterium glucuronolyticum and were compared with the type strains of the recently proposed species Corynebacterium glucuronolyticum and Corynebacterium seminale. The two type strains as well as the clinical strains were shown by DNA-DNA hybridization and sequencing of the 16S rRNA gene to be related at the species level. All strains were classified as C. glucuronolyticum, because this name has nomenclatural priority over C. seminale.